I can see why they'd make a connection between censoring of porn and the tentacle thing, but betentacled beasties were lusting after Japanese women since long before westerners started influencing-writing Japanese laws. Look something up called "Dream of the fisherman's wife". Not at work obviously.

As /u/zhemao points out, the Japanese had been using guns since the 16th century. It's also not true that there was no trade between Japan and the outside world before Perry kicked the doors in. Before 1635 the Japanese actively traded with the outside world. After the Shogun banned foreign travel, Chinese and Dutch traders continued to visit Japan. The Dutch traders were confined to Dejima, a small island in the bay of Nagasaki.

The beginning of the part about consumer culture is not at all accurate. Japanese daimyo were rather quick to adopt the European matchlock musket after it was introduced by the Portuguese in the late 16th century. The use of natively produced matchlock muskets (tanegashima) revolutionized warfare in the late Sengoku (Warring States) Period. It was only after the Sengoku Period ended and Japan was united under the Tokugawa Shogunate that guns were banned. And this wasn't to keep peasants from killing Samurai too easily, it was to prevent the recently subjugated regional lords (read: other Samurai) from threatening the power of the central government (which, of course, was the only group allowed to have guns). The need to hold onto political power was also the reason the Tokugawa government adopted an isolationist policy (Sakoku) which cut Japan off from foreign contact (with the exception of the tightly controlled Dutch traders at Dejima).